Tires, plastic bottles, and general trash washed up by the sea litter the beaches in Prestwick, Scotland, 22 March 2005. Christopher Furlong/Getty Images The world's oceans are awash in plastic pollution, and as these maps and charts show, the situation is poised to worsen unless drastic changes take place.

Over the coming decades global plastic production is slated to increase nearly sixfold, and collection and recycling systems in many parts of the world already are struggling to keep up with the proliferation of plastic products and associated waste.

Broadly speaking, plastic pollution comes from three main sources: single-use applications such as food packaging and disposable consumer goods; long-lasting plastic items, including pipes and construction materials; and durable consumer products such as electronics and furniture.

The impacts of plastic — and in particular, microplastic — on marine life can be devastating. Hundreds of species of seabirds, turtles, seals, sea lions, whales and fish have suffered entanglement or death due to plastic pollution in recent decades.

This collection of maps and charts prepared by Norway-based GRID-Arendal— a United Nations Environment Programme affiliate and partner with a mission of creating environmental knowledge to enable positive change — explains how plastic ends up in the world's oceans and explores steps being taken to reverse this trend.

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Pathways to pollution

Graphic by GRID-Arendal and Maphoto/Riccardo Pravettoni and reprinted with permission

One of the major challenges of addressing plastic pollution in the world's oceans is the fact that sources of entry are multiple and widespread.

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Mismanagement

The global production of petroleum-derived plastic has increased dramatically, from 1.5 million metric tons (1.7 million tons) in 1950 to more than 300 million metric tons (330 million tons) in 2014. If the current production trend — approximately 5 percent increase per year — continues, another 33 billion metric tons (36 billion tons) of plastic will accumulate around the planet by 2050, further driving the need for better methods of collection and recycling.

Plastic currents

The geographic distribution of marine plastic debris is strongly influenced by the entry points and different ocean transport pathways, which are in turn determined by the density of plastic debris coupled with prevailing currents, wind and waves.

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Entangled marine life

Entanglement can cause death due to drowning, starvation, strangulation, or cuts and injury that cause infection. Much of the damage to marine life of this nature is caused by discarded fishing equipment — so-called "ghost fishing." Studies of scarring on whales from the Gulf of Maine indicate that more than 80 percent of right whales and 50 percent of humpback whales have experienced entanglement in fishing gear.

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Marine debris ingestion

The ability of plastic particles in the ocean to attract organic chemicals that don't dissolve, which include many well-known toxic substances, has led to a growing number of studies looking at plastics as a source of toxic chemicals in marine organisms.